Silencer for internal combustion engines



March 11, 1941. w. P. WOLD 2,234,612

I SILENCE! FOR INTERNAL COIBUSTION Grills Filed Aug. 4, 1938 I I f0 III/l/I/ I/IIIIIII/l.

Patented Mar. 11, 1941 UNITED STATES SILENCER FOR INTERNAL COLIBUSTION ENGINE Wilhelm Petersen Wold, Oslo, Norway, assignor to Wilhelm Petersen Wold and Adoll' Eger, both of Oslo, Norway Application August 4, 1938, Serial No. 223,130 In Denmark February 23, 1938 6 Claims.

The subject of the invention is an improved silencer especially adapted to be fitted to the exhaust pipe or an internal combustion engine. Characteristic to the invention is the feature that the exhaust gases are passed through the silencer without changing their direction to a substantial degree, so that no pressure and power are lost by abrupt change of the direction. In the silencer according to the invention cross walls in the path to be traversed by the exhaust gases are dispensed with and the exhaust gases are not passed along zig-zag lines or forced to change their direction sharply. We have succeeded in reducing the resistance considerably by avoiding abrupt alterations of pressure and eddy motion.

' According to the invention in a large elongated chamber, suitably of circular or oval crosssection, is fitted a narrower pipe serving as outlet from the chamber, and shaped to cylindrical or conical form, preferably in the form of a frustum having preferably its reduced open and disposed toward the outlet. The pipe is closed at its opposite end and may terminate freely within the said chamber. In the 'wall of said pipe are provided several openings having collectively a crosssection equal to the inlet opening. The exhaust gases pass preferably into the large chamber and leave the latter, without altering their general direction of flow, through the openings into the narrow outlet pipe through the open end of which the gases are discharged. In this way the exhaust is divided during its passing through the openings into several currents parallel to each other, substantial loss of pressure being avoided since the total cross-section of the openings is comparatively large and the gases maintain substantially their original direction.

The mouth of the outlet pipe may be widened in the direction of the motion of the exhaust gases so as to secure a gradual passage to the atmosphere.

In a modified construction two pipes may be placed in the elongated chamber, viz., a distributing pipe having a construction known per se by which the exhaust gases are passed from the internal combustion engine into the chamber and an outlet pipe discharging the exhaust gases from the chamber to the atmosphere. Such pipes may, if desired, be made as a unit and be disposed co-axially, the two parts of the pipe being separated from each other by a cross wall.

Silencers of the present construction may expand freely when heated and may be easily disassembled for cleaning.

with the easier discharge there is obtained better combustion, and the engine is not inclined to smell even when burning crude oil owing to the fact that the silencer is evacuated at each stroke owing to the small resistance in the silencer.

Further, the cooler is substantially unloaded.

An engine, furnished with a silencer in accordance with the invention is silent especially also owing to the fact that there are no surfaces which may reiiect sound. Further, an enne furnished with such a silencer uses a smaller quantity of petrol per horse-power unit than the same engine furnished with a silencer of the well known commonly used constructions.

Experiments have proved that 10 to, 15% economy is obtained depending upon the size of the engine, that is to say upon the horse-power, the maximum effect being obtained usually by larger engines. The traction force is better and the working is more economical when using a silencer according to the invention than when using commonly employed silencers.

Some forms of the invention are shown by way of example in the accompanying drawing in which: r v

Fig. 1 shows a silencer for a large engine, for example, an automobile engine.

Fig. 2 shows a silencer for a smaller engine, as for example an engine of a. motor cycle.

Fig. 3 illustrates a slightly modified form of the silencer in which a portion of the structure of Fig. 2 is combined with the structure of Fig. 1.

Fig. 4 illustrates a further modification of the structure of Fig. 2.

Fig. 5 illustrates in side elevation a portion of the interior unit of the structure of Fig. 4.

Fig. 6 is a sectional view on the line 6-4 of Fi 5.

In Fig. 1, l' designates a cylindrical chamber of a silencer to a rigid end wall of which is connected a branch pipe 2 connectible to the exhaust pipe from an internal combustion engine. A cylindrical or conical outlet pipe is fitted in a removable end wall at the opposite end of the chamber and may be supported by stiflening means. Such outlet pipe 3 extends with a part 5 into the chamber. It may suitably extend to about the central part of the chamber.

The pipes 3, I and the pipe 2 may be disposed co-axially relatively to the chamber l. The end of the part I next to the pipe 2 may be closed. preferably by a conical piece i, in order that the resistance to the inflowing exhaust gases may be as small as possible.

In the wall oi the part I are apertures l for a several ways.

passage of the exhaust gases. The apertures may be arranged in rows and may have a total cross section about as great as the inlet, or better, slightly greater, according to the size of the engine. The gases pass along the paths denoted by arrows 8. It appears immediately from the figure that the exhaust gases flow substantially along stream-lined paths when passing through the silencer.

In Fig. 2 is shown a silencer consisting of a chamber having a divided pipe, the first part of which serves as a distributing pipe, while the rear part serves as a discharge pipe from the chamber. In a chamber 9 is fitted a removable conical pipe I!) which is divided into two by means of a wall ll substantially at the middle part of the pipe. The wall Il may be plane or may be conical as indicated by dotted lines at 12. With suitable dimensions of the conical part E2 the speed of the exhaust gases may remain substantially unchanged during their passage through the first part of the pipe II].

In the wall of the pipe are openings 13 and M.

That end of the pipe l which is connected to the discharge pipe is supported by the end wall l of the chamber 9 while its opposite end is supported by its opposite end wall it. At the discharge end of the pipe there may be arranged a divergent mouth in the form of a funnel H. The exhaust gases pass along paths indicated by arrows l8.

The shape of the openings may be varied in They may be bored cylindrically and their axes be arranged at right angles to the axis of the pipe 5 or the pipes l3, 14. However, it is preferred to arrange them in an inclined position.

Further, the openings may be arranged as longitudinal slots, or as cross-slots having inclined edges. They may also be arranged along helical lines. Their walls may be arranged at an acute angle.

The form of the invention shown in Fig. I may have combined therewith, if desired, a rearwardly diverging funnel-shaped mouth such as is shown in connection with the structure of Fig. 2 and indicatedby the numeral ll. Such modified form of the structure of Fig. 1 is illustrated in Fig. 3 in which the cylindrical chamber is indicated by the numeral I having therein the rearwardly tapering pipe 5' provided with apertures 1' and having a portion of its rear end, indicated at 3' extending outside the chamber I. This rear portion 3' has connected therewith the rearwardly divergent mouth 20.

The openings of the silencer devices may also have associated therewith deflector hoods such, for example, as is illustrated in Fig. 4, where there is shown a form of silencer corresponding to the one shown in Fig. 2, the cylindrical chamber or body portion of which is indicated by the numeral 9'. Extending through this chamber is the continuously tapering pipe l0 having intermediate its ends apartition H and at the two sides of the partition gas outlet and inlet openings 13 and M, respectively. The rear end of this pipe joins a rearwardly divergent mouth body of conical form which is indicated by the numeral H. Surrounding the pipe ID are two series of deflector hoods, those of the series which is indicated by the numeral 2| encircling the gas outlet apertures l3 and being directed toward the rear of the chamber while those of the other series which is indicated by the numeral 22, encircle the gas inlet apertures l4 and are directed forwardly in the chamber so as to receive the gases flowing rearwardly from the rearwardly directed and divergent hoods 2|.

Fig. 5 shows how the hoods 2i and 22 may appear in elevation and as shown in this figure, the hoods may extend directly transversely of the pipe of which they form apart, here indicated by the numeral l0" and corresponding to the pipe of Fig. 4, or the hoods may be disposed obliquely as indicated at 22' if such disposition is found to be desirable.

Fig. 6 illustrates one method of securing the hoods around the pipe ll!" over the apertures therein, the hoods shown upon this pipe and extending at right angles to the axis thereof being designated by the numerals 2i and the apertures which the hoods cover being designated by the numeral 83''.

According to another form the openings may be arranged as longitudinal slots having guide faces.

Instead of using a single outlet pipe, especially in connection with large engines several outlet pipes may be arranged in the same chamber.

I claim:

1. A silencer for combustion engines, comprising a casing forming a chamber, means for introducing engine exhaust gases through one end of the easing into the chamber, a gas conducting conduitin and extending longitudinally of the casing, and having an inner and terminating within the casing and tapering from such end to the other end and having the reduced end extending through a wall of the casing to the exterior thereof to form a gas discharge port, the inner end of the conduit being closed and directed toward the said inlet means and said conduit having apertures formed in the wall thereof in that portion lying within the chamber.

2. A silencer for combustion engines, comprising a casing forming a chamber, means for introducing engine exhaust gases through one end of the casing into the chamber, a gas conducting conduit in and extending longitudinally of the casing and having an inner end terminating within the casing and tapering from such end to the other end and having the reduced and extending through a wall of the casing to the ex terior thereof to form a gas discharge port the inner end of the conduit being closed and directed toward .the said inlet means and said conduit having apertures formed in the wall thereof in that portion lying within the chamber, and a hollow funnel-like body connected at its apex with the said reduced end of said conduit and discharging rearwardly therefrom.

3. A silencer for combustion engines, comprising an elongated casing forming a chamber, a pipe extending through the. entire length of the casing and having its ends projecting through opposite walls of the casing, said pipe being of constantly decreasing diameter from one end to the other and having a maximum overall diameter materially less than the inside diameter of the casing/the end of larger diameter constituting a gas inlet for the silencer, the end of the pipe of smaller diameter constituting the gas outlet, partitioning means within the pipe, and said pipe having a plurality of apertures in the wall thereof at opposite sides of said partition and lying entirely within the chamber whereby gases entering the inlet end of the pipe will be diverted into the chamber and returned into the pipe for escape through the outlet end thereof.

4. A silencer for combustion engines, comprising an elongated casing forming a chamber, a pipe extending through the entire length of the casing and having its ends projecting through opposite walls of the casing, said pipe being of constantlydecreasing diameter from one end to the other and having a maximum overall diameter materially less than the inside diameter of the casing, the end of larger diameter constituting a gas inlet for the silencer, the end of the pipe of smaller diameter constituting the gas outlet, partitioningmeans within the pipe, and said pipe having a plurality of apertures in the wall thereof at opposite sides of said partition and lying entirely within the chamber whereby gases entering the inlet end of the pipe will be diverted into the chamber and returned into the pipe'for escape through the outlet end thereof, the said casing at the end adjacent the outlet end of the pipe being extended beyond the wall through which the outlet end of the pipe passes, and a funnel body connected at its apex with the said outlet end of the pipe and joined to the extended portion of the casing and discharging away therefrom.

5. A silencer for combustion engines, comprising a casing forming a chamber, means for introducing engine exhaust gases through one end of the casing into the chamber, a gas conducting the casing, said conduit being tapered from one end to the other and having the reduced end extending through a wall of the casing to the exterior thereof to form the gas discharge port, the inner end of the conduit being closed and directed toward the said gas introducing means and said pipe having apertures formed in the wall thereof in that portion lying within the chamber, and deflecting hoods carried by said conduit and extending over said apertures and directed toward the outlet end of the conduit.

6. A silencer for a combustion engine, comprising a casing forming a chamber, means for introducing engine exhaust gases through an end of the casing into the chamber, means forming a conduit within the casing and opening through the opposite end thereof to provide a gas discharge port, the conduit forming means tapering throughout its length toward the said opposite end of the casing and having gas inlet apertures in the portion of the side wall thereof lying within the casing by which gas may flow from the casing into the conduit along paths extending angularly to the path of flow of the gas in entering the casing through the first-mentioned end.

WILHELM PETERSEN WOLD. 

